This invention relates to an improved mechanism for the combination lock of suitcases, luggages or the like.
The characteristic features of this invention consists in two aspects. Firstly, it is free of the risk of undesired alteration of the code. Secondly, the eyelet of the latch flap can still be pressed into the hole of the lock even when the latter is not adjusted to the correct code.
Currently available combination locks for suitcases with changeable code suffer two disadvantages. Structurally, all such locks have a spring-loaded shifting shaft which is directly in mechanical connection with the actuating knob and directly actuated by the latter to shift between a locking position and an unlocking position. A plurality of (practically three) number wheels are mounted on the lock and centrally passed through by the shifting shaft. Please refer to FIG. 14A. Corresponding to the number wheels (12'), the shifting shaft (6) carries a plurality of wards. Each number wheel (12'), corresponding to a ward (a), is provided with a notch. When all number wheels are adjusted to the correct code so that their notches (b) are in alignment with the corresponding wards, the shifting shaft is permitted to shift to the open position. Otherwise the shifting shaft is hindered by the number wheels which are not correctly dialed. FIG. 14A illustrates an example of unchangeable code. In the case of changeable code (please refere to FIG. 14B), the ward is carried on an inner wheel (c) which is rotatably but not axially slidably mounted on the shaft. When it is desired to change the code, one must first set the lock in the correct code and keep the knob in the "open" position so as to retain the shifting shaft in the unlocking position. Now all the wards of the inner wheels are in engagement with the number wheel so that an inner wheel can be driven to rotate together with its corresponding number wheel to a new position, therefore renewing the code. The inner wheel is not necessarily provided with a ward. Alternatively it can be provided with a notch or slot. In this case, a corresponding ward or projection can be provided on the housing or wheel retainer. FIG. 14C and FIG. 14D (The fragmentary view of FIG. 14C) illustrate a preferred example. The inner wheel (14') has the shape of a gear with teeth (d), but a tooth is lacking, thus forming a bigger interdental space (e). The interdental space thus serves as an equivalent of a notch. A projection (f) is provided in the route of the inner wheel. When correctly dialed, the inner wheel has its notch (e) in alignment with the projection (g). This invention relates to the improvement on this type.
The conventional combination lock typically has a complicated construction. Further, the conventional combination lock is subject to the risk of having the code unintentionally altered if the wheels are disturbed during unlocking operation. Moreover, in order to press the latch flap into the locking position, the conventional combination lock suffers the disadvantage that is must first be set to the proper code.
Accordingly it is the main object of this invention to provide a combination lock of simplified construction and use which is free of the risk of undesired alteration of the code.
It is another object of this invention to ensure the code-changing position not to be entered unless desired, thus totally eliminating the risk of undesired alteration of the code by any possible undue operation, and to provide a securing means to retain the knob in code-changing position so that one can change the code without using an extra hand to keep the knob in this position.
It is the third object of this invention to provide a combination lock, which allows the flap to be pressed into its locking position regardless of whether or not the lock is correctly adjusted to its correct code.
The first object is achieved by a shifting shaft having three positions instead of two in conventional locks: a locking position, an unlocking position and a code-changing position. Only in the code-changing position can the code be changed. The middle position is the locking position, while the two end positions are respectively unlocking position and code-changing position. The middle, locking position is the balance position of the spring-loaded shifting shaft. In both end positions, the spring is compressed and when no external force is applied, the shifting shaft will resiliently return to the middle position. The three-position-mechanism can be applied to various devices of code-changing mechanism, but here we only discuss the case of FIG. 14C. When a suitcase provided with such lock is desired to open, dial the number wheels to the correct code, then shift the knob to the unlocking position. In so doing the suitcase is opened. This operation is exactly the same as with a conventional lock. On the other hand, when it is desired to change the code, set the number wheels to the correct number and then shift the knob to the code-changing position, and then dial the number wheels to the desired new number. Thus, when the inner wheels return resiliently to the middle position where they re-engage with the number wheels, the code is changed to the new number.
Even if the number wheels are not unintentionally altered while unlocking the suitcase, there are still minor possibilities of undesired change of code by undue operation, though the probability is very small. A user may inadvertently shift the knob to code-changing position instead of to the unlocking position even when it is not desired to change the code. To prevent entry to the code-changing position, one can easily use a small piece of plastic, wood, or other stiff material which blocks the way of the knob from the locking position to the code-changing position. But such a blocking piece causes unslightly appearance of the lock, and it is liable to fall out from its blocking position. Accordingly, the second object of this invention is to provide a blocking mechanism which hinders the entry into the code-changing position. When it is desired to change the code, the knob must be released from the blocking mechanism to make possible its entry into code-changing position. Practically, the blocking mechanism is provided directly on the knob, and can be shifted up and down along the surface of knob between two positions, namely blocking and unblocking positions, in a direction perpendicular to the shifting of the knob. Preferably, the knob is divided into two parts, a knob frame, and a blocking switch, which makes the blocking mechanism. Preferably the blocking switch is retained in either of the blocking or the unblocking position rather than resiliently biased toward one of the two positions. In whichever position, the blocking switch is carried by the knob frame to shift among the locking, unlocking, and code-changing positions as an entity. When the blocking switch is normally in its blocking position, it will be blocked by a projection housing of the lock, so the knob cannot be pushed to its code-changing position. When the blocking switch is switched over to its unblocking position, it is no longer blocked by the housing, and the knob can now be shifted to its unlocking position.
When the knob reaches its code changing position, if the user pushes the blocking switch back to its blocking position, the projection, which previously blocked the way to the code-changing position, will now block the way returning to the locking position. Therefore the knob can be secured in code-changing position without applying an extra external force. When the new code has been readjusted, push the blocking switch up its unblocking position, and the knob will resiliently resume its locking position. Now the code has been changed, and the blocking switch can be switched back to its normal blocking position.
The third object is achieved by a latch member which is not fixedly mounted on one end of the shifting shaft. In conventional combination locks, the latch member for locking the latch member is generally fixed on one end of the shifting shaft or forms as an integral part of the latter. For this reason, the latch member must move synchronously with the shifting shaft. If the code is not correctly adjusted, the shifting shaft is hindered by the number wheels and cannot move. Hence the latch member cannot move, and the latch flap cannot be pressed into locking position. In the present invention, the latch member is not fixed, but resiliently supported and retained at one end of the shifting shaft, and therefore can be axially pressed a small distance toward the opposite end of the shaft. Thus even if the number wheels are not in correct position and the shifting shaft cannot move, when the latch flap is swung down and its eyelet is pressed into the latch hole, the latch member is pushed aside by the eyelet of the latch flap and then resiliently engages with the eyelet.
This invention will be better understood when read in connection with the accompanying figures. In order to help the reader to understand the orientation of the elements, X, Y, Z coordinates have been shown in some of the figures to indicate respectively the width, height and depth orientation of the lock.